Safety device against rupture of a rotary shaft

Abstract

A safety device used in case of rupture of a rotary shaft for preventing the shaft from rotating and for preventing broken portions thereof from falling, includes at least one safety element placed so as to retain the shaft to prevent it from falling. The peripheral surface of the shaft and a facing surface of the safety element are provided with mating devices that cooperate to prevent the shaft from rotating when a portion of the shaft is retained by said safety element due to the shaft rupturing. The device is particularly suitable for use with a shaft that winds up lifting straps for a raisable curtain or that winds up the curtain itself.

I claim: 
     
       1. A safety device operable in the event of rupture of a rotary shaft for preventing the shaft from rotating and for preventing broken portions of the shaft from falling, for use with a shaft that winds up one of lifting straps for a raisable curtain and the curtain itself, characterized in that at least one safety element is placed below and along a substantial portion of the shaft to retain the shaft to prevent it from falling, wherein a peripheral surface of the shaft and a facing surface of said safety element comprise means for cooperatively preventing the shaft from rotating when a portion of the shaft is retained by said safety element due to the shaft rupturing. 
     
     
       2. The device according to claim 1, wherein the safety element comprises a bracket surrounding the bottom portion of the shaft, an inside of the bracket being provided with a first member and the surface of the shaft also being provided with a second mating member suitable for engaging said first member to thereby lock said shaft. 
     
     
       3. The device according to claim 2, wherein said second mating member comprises at least one longitudinal slot and wherein said first member comprises a rib disposed substantially parallel to said longitudinal slot. 
     
     
       4. Device according to claim 1, wherein said shaft is a hollow shaft, wherein the safety element is a rod disposed inside the hollow shaft, the inside peripheral wall of said hollow shaft including a mating member for engaging with said rod so as to prevent shaft rotation. 
     
     
       5. The device according to claim 4, wherein said mating member comprises at least one rib protruding from said inside peripheral wall of said hollow shaft. 
     
     
       6. A safety element for a roll up door including a shaft suspended above a door way, said safety element comprising: first means disposed parallel to the length of the shaft for supporting the shaft in the event of a shaft rupture, which rupture thereby moves a ruptured portion of the shaft into contact with said first means; and   second means for preventing rotation of said ruptured portion of the shaft when the ruptured portion of the shaft moves into contact with said first means.   
     
     
       7. The safety element as recited in claim 6, wherein said first means comprises a bracket disposed beneath said shaft. 
     
     
       8. The safety element as recited in claim 6, wherein said second means comprises: a first member operatively supported beneath said shaft;   a second mating member connected to said shaft and opposing said first member for engaging said first member when said ruptured shaft is moved into contact with said first means.   
     
     
       9. The safety element as recited in claim 8, wherein said first member is a male member and wherein said second mating member is a female member. 
     
     
       10. The safety element as recited in claim 8, wherein said first member is a male member and wherein said second mating member is a male member. 
     
     
       11. The safety element as recited in claim 6, wherein said shaft is a hollow shaft, wherein said first means is a rigid rod member, and wherein said rod member is disposed inside of said hollow shaft. 
     
     
       12. The safety element as recited in claim 11, wherein said second means comprises: said rod member;   a mating member provided on an inside surface of said hollow shaft, said mating member being brought into engaging contact with said rod member when said ruptured shaft is moved into contact with said first means.